1. Field of the Invention
The present invention relates to mechanisms for providing a stamp or endorsement to a single side of a document, generally referred to as document endorsers, and more particularly to a method for controlling the rotational print head of such a mechanism in order to minimize power consumption requirements of the device.
2. Prior Art
It is well-known in the bank check sorting art to provide a document endorsing apparatus for normally endorsing the back side of checks as they are individually fed to a sorting apparatus. The most common type of endorsement mechanism employed are those having a document feed means and a rotational printing drum having an ink stamp affixed to the drum surface so that with each revolution of the drum the stamp is properly inked and brought into position such that the document and drum are moving at a similar rate to provide endorsement to the back of the check.
Originally, the rotational print head was constantly rotated such that the actual position of the endorsement was haphazardly placed on the back of the check. Thereafter the mechanism was provided with a means to accelerate the print head responsive to a document entering the endorser for placing the endorsement at a predetermined location on the check. But because the documents were randomly spaced as they moved along a track to the endorser, it was found necessary in order to keep the printing position uniform to accelerate the rotational print head to printing velocity and then decelerate the head back to zero velocity before a subsequent document entered the endorser. To perform the rapid acceleration and deceleration of the print head, energy consumption by the print head motor was relatively high making it necessary to utilize a motor having high power consumption requirements.
Thus, it would be highly welcome in the endorsing art to provide a control method allowing a less powerful motor operated with lower power consumption requirements to accomplish the proper placement of an endorsement to a single side of randomly spaced documents entering an endorser.